This book serves as a key to the deciphering of melodies written in the Middle Byzantine notation. In addition, it offers an introduction to Byzantine chant in a wider sense, dealing with topics such as chant transmission before the neumes, the varieties of Byzantine musical notations, words and music in Byzantine chant, Byzantine and Western neumatic notations, modes, melody and intervals, and the development of the musical genres. Coming into use around AD 1150, the Middle Byzantine musical notation is the earliest notational type from Byzantium that can be transcribed with reasonable accuracy. Consequently, the musical content of manuscripts earlier than c. 1150 can only be fully understood through Middle Byzantine versions. The Middle Byzantine notation continued to be used in Greek Orthodox Churches until the beginning of the 19th century. The book presents a panorama of the styles of Byzantine chant, ranging from simple psalmody to highly elaborate and melismatic pieces. To illus